Your requirements could not be resolved to an installable set of packages. Problem 1 - Root composer.json requires php ^7.0 || ^8.0 but your php version (5.6.40) does not satisfy that requirement. Problem 2 - symfony/css-selector[v4.4.0, ..., v4.4.10] require php ^7.1.3 -> your php version (5.6.40) does not satisfy that requirement. - symfony/css-selector[v4.4.11, ..., v4.4.44] require php >=7.1.3 -> your php version (5.6.40) does not satisfy that requirement. - symfony/css-selector[v5.4.0, ..., v5.4.26] require php >=7.2.5 -> your php version (5.6.40) does not satisfy that requirement. - symfony/css-selector[v6.0.0, ..., v6.0.19] require php >=8.0.2 -> your php version (5.6.40) does not satisfy that requirement. - symfony/css-selector[v6.1.0, ..., v6.4.0] require php >=8.1 -> your php version (5.6.40) does not satisfy that requirement. - symfony/css-selector v7.0.0 requires php >=8.2 -> your php version (5.6.40) does not satisfy that requirement. - Root composer.json requires symfony/css-selector ^4.4|^5.4|^6.0|^7.0 -> satisfiable by symfony/css-selector[v4.4.0, ..., v4.4.44, v5.4.0, ..., v5.4.26, v6.0.0, ..., v6.4.0, v7.0.0].